Means for controlling wells



Dec. 28, 1937. F2. A. MUELLER MEANS FOR CONTROLLING WELLS original Filled oct. 26,' 19s] 4 Sheets-Sheet 1 ROBERT A. MUELLER.

ln/Denton Dec. 28, 1937. R. A. MUELLER MEANS FOR CONTROLLING WELLS Original Filed Oct. 26, 193] 4 Sheets-Sheet 2 S11/Danton dwz/m44 a ROBERT A. MUELLER Dec. 28, 1937. R. A. MUELLER MEANS FQR CONTROLLING WELLS `Original Filed Oct. 26, 193] AWM 4.- RoERT A. MUELLER 3mm/nto@ gem @PM dbkouwqs Dec. 28, 1937. fR, A. MUELLER 2,103,431

MEANS FOR CONTROLLING WELLS Original iled Oct. 26, 195] 4 Sheets-Sheet 4 gmxmtoz z @hm dum/wup,

Patented Dec. 28, 1937 N UNITED STATES l 2,103,431 MEANS FOR. CUNTROLLING WELLS Robert A. Mueller, Houston, Tex.

Application October 26, 1931, Serial No. 571,099 Renewed September 19, 1936 7 Claims.

'Ihe inventiomrelates to an improvement in the means and method yof controlling the iiow from wells and particularly at the time the tubing is being inserted in` the well and the drilling mud removed therefrom after the drilling has been completed.

The critical time in bringing in a well to produce oil or gas, is that time directly after the drilling vof the well has been completed, and when the well bore is full of mud which has been used to 'maintain the walls of the well bore during the drilling operation, and to remove the cuttings from the bit. When the drilling has been completed the drill bit is removed by withdrawing the drill stem and it is then necessary to run in the tubing and liner, if a liner is to be used. YIt is usual to provide a screen or perforated areaon the lower end of either the casing, tubing, or the liner asthe case may be, in order to allow the oil to enter or to filter out the sand encountered with the oil. 'I'he openings of these strainers or filters are very small in order to eliminate fine sands and are usually measured in thousandths of an inch. This strainer must be in-` serted in the well while the well is full of mud as the mud overcomes and holds back any pressure in theformation so that the tubing .can be run into position. It seems apparent, therefore, that the strainer openings will be filled with mud and itis absolutely essential to wash the mud not only from the strainer but also from the formation in order that a full 'flow of oil will be obtained. The present invention relates toa means and method of running in the perforated casing or lter screen, washing the same, and positioning the strainer tubing and tubing head in such a manner that positive and complete control of the flow from the well will be had at all times during the operation. 1 v

A 'great many wells are ruined at-the critical period when the tubing or strainer is beingl run into the well, due to the fact that the well is not washedproperly, and the mud clogs up the formation or the strainer or both, and it is with the idea of providing an assembly of equipment and a method of manipulating the same which will permit complete washing of the weiland positive control of the same during the period when the heavy mud is being removed and replaced by clear water, that the present method and structure has been devised.

It is one of the objects of the invention to disclose a means and method for controlling wells during that period when the flow is being brought in which will assure complete control at all times.

Another object of the invention is to provide an improved assembly of devices which will cooperate with each other when the well is being brought in so that any pressure encountered in either the casing or the tubing may be properly 5 controlled to prevent a. blowout of the well.

Another object of the invention is to disclose a method of washing the well to remove the mud therefrom in lwhich oo mplete control of the flow of iiuid from the well may be had.

It is also an object of the invention to provide in combination mechanism to close the casing about the tubing, to close the casing in event there is no tubing or drill pipe therein, and to also close the tubing while it is in position.

A still further object of the invention is to provide a mechanism for closing the tubing against back pressure and providing additional means to close oil? the tubing when the tubing head is to be connected thereto after the well has been washed.

A still further object of the invention is to provide a mechanism for closing the casing about the tubing, and, if necessary, support the tubing upon this means in combination with a mecha- 2 nism for closingl the tubing so that the entire well area will be cut off below the location of any openings in either the casing or the tubing.

- A still further object of the invention is to provide a mechanism which will permit running of the tubing against the well pressure and a further mechanism for closing the tubing in event excessive well pressure is encountered.

Another object of the invention is to provide va means and method for performing the necessary operations in the bringing in of a well with the well under mechanical control at all times, together-with a means to permit changing of any or all of the ow line fittings leading from the well head, either simultaneously or independently.v

It is also an object of the invention to position a closure member on` the well casing below all outlets so that the well may be completely closed by the manipulation of the single member in event there is no pipe in the Well casing.

The method of bringing in wells claimed herein may be practiced by the apparatus disclosed in my prior copending application No. 530,649, filed April 16, 1931, for a combination tubing hanger and blowout preventer, which has matured into Patent No. 1,909,304 dated May 16, 1933. It is to be understood, however, that the method may be practiced with'apparatus other than that shown in the above mentioned patent.

, bottom of the well bore.

The method invention is therefore understood to be separate and divisible from the apparatus invention claimed in my patent, but the present application is a continuation in part of my prior application Serial No. 530,649, insofar as common subject matter is concerned.

It is to be understood that various other objects of the invention will appear as the detailed description of the invention proceeds, and that various alterations and modincations of the method and apparatus may be used without departing from the spuit of the invention, as disclosed in the following description and drawings wherein:

Fig. 1 is a side elevation of a well bore which is equipped with the apparatus of this invention and showing certain of the parts in section, with the wash pipe lowered to the very base of the well in order to wash the mud from the well.

Fig. 2 is a view similar to Fig. 1, but showing the l wash pipe or tubing raised from the bottom of the well in order to wash the inside oi the casing or liner so that the well may be completely cleaned.

Fig. 3 is an elevation of the well head assembly andv showing the arrangement of the structure when the tubing head is being attached to the tubing after the well has been washed.

Fig. 4 shows a slightly modified form of the Jstructure of Fig. 3 in position after the tubing head has been landed and the well is ready for production.

Fig. 5 is substantially identical with Fig. l, with the exception that the valve head in the present figure is positioned below the blowout preventer.

By having reference to Fis. l, the well bore is indicated generally at 2, and the particular portions illustrated disclose the oil bearing formation which is usually encountered below some cap rock or solid formation. The well bore shown is that which has been formed by the drill bit when it penetrated the oil formation 3. In the particular` well illustrated in these drawings, it is intended to show what is known as a full casing; in other words, the casing extends from the surface to the The' string of casing may or may not be of the same diameter throughout. Some operators prefer to set a casing of this type as they are then assured that there will be no caving of the well, and its future is to be assured. Many operators, however, prefer to set only a portion of the casing. and rely uponthe solid formation to maintain the well bore. It is to be understood that this invention may be practiced with either type of operation, but the casing I, which is illustrated, extends from the casing head 5 to the base 6 of the well.

While the drawings show this string of casing as lowered to the bottom of the well, it is'to be understood that thef invention may be practiced by setting the casing. on top of a hard .formation and allowing the oil 'to enter the lower end of the' casing or the casing may be cemented in position at any'desired elevation.

When the casing is set above the sand it is usual to setjthe casing, and drill into the sand after the cas'ing has been anchored. When this procedure is adopted, which is the rule rather than the exception. a liner or perforated pipe is then lset from the lower end of the casing to extend into the oil formation, and this liner will be packed of adjacent the bottom of the casing at any desired elevation. It is intended that the invention may be practiced with any type of casing, screen, or liner setting. With the device in position, as l shown in Fig. l, the casing 4 has-been run while the formation pressure was overcome by the heavy mud in the well. and after the blowout preventer l has been properly positioned in some instances it may be desirable to set a gate valve I' thereon which will be available to close the casing in event the formation pressure overcomes the weight oi the fluid in the well at a time when there is no pipe or tubing inside of the casing.

This valve is preferably positioned solely 'for this emergency. *Abovve 'this gate valve I' is illustrated one form of a tubing head 0', which is provided with the flow lines Il and II. It is usual for these now lines to be equipped with valves I2 so that they may be closed. With this set up of fittings it is possible with the blowout preventer I to close the casing .when there is a string of tubing such as I3 in the casing. This is accomplished because the blowout preventer l is provided with rams I4, which have cutaway faces thereon, such as I4', which ilt about a pipe. Thus the blowout preventer will be equipped with rams arranged to fit about a tubing of the size which is being run into the well.

When these fittings 5. 8', and l have been positloned on top of the casing it is then necessary to run in the string of tubing Il and this tubing is assembled as it is lowered into the well until the lower end thereof approaches the bottom of the well. At this point a stop cock I5 is connected to the section of tubing I6, which is at that time the uppermost section of tubing. This stop cock may be of any desired type but has here been shown having a plug valve Il therein which is arranged for rotation by connecting a wrench or other tool to the head I8. When this plug is rotated through 9'0" the opening I9 therein will be transverse of the passage through the tubing and completely close the passage in the tubing string. Above this stop I5 is positioned a back pressure valve 20. This valve may be of any desired type which will close when any pressure occurs from below the valve. Various types of these valves are well known and one standard make has been illustrated which includes the valve member 2 I which is arranged to seat at 22 to close the passage through the valve housing 23, and is arranged to be lifted to this closed position by contact of the fluid on the lower side of the valve member.

Preferably this stop ,cock I5 and the back pressure valve 20 are positioned closely adjacent each other with the back pressure valve above the stop cock. When these two valves have been placed upon the tubing another section of tubing is attached thereabove and the tubing further lowered into the well so that the nipple 25 will engage with the seat 26 carried by the set shoe 1 on the lower end of the casing.

With the parts positioned, as above described, and the well still full of heavy mud, the operation of bringing the well into production is the next step. It is to be understood that the perforations 9 in the casing have undoubtedly become clogged with debris and heavy mud while the casing was being run into the well. As previously stated, these perforations may be in the lower sections of the string of casing 4 or they may be a special liner or a second full string of casing. Regardless of the type of pipe in which these perforations are made, it is necessary to remove the heavy mud to enable the well to iiow freely. The heavy mud. which has been in the well, overcomes the pressure of the oil and gas in the formation, but as water is circulated down through the string of pipe I3, it displaces the heavy mud and dilutes the same. A continued circulation of this water through the tubing serves to gradually reduce the specific gravity of this column of fluid is reduced to vsuch an amount that it is less than the formation lpressure, the pressure of the formation will then begin to enter the well bore. It seems obvious that as the heavy mud is gradually removed from the well and is replaced by a column of water that the danger of a blow out in the well is proportionately increased; therefore, as the washing of the well proceeds, the danger of a bloyv out increases, and every'precaution must be used in order to provide mechanisms which will close the tubing as well as the casing almost instantly when the formation pressure overbalances the weight of the column of uid in the well.

, The present invention contemplates the provision of means by which the well can be completely closed in at all times while the tubing is being run into position, while the well is being washed, and while the connection of the fittings or manifold for the flowing of the oil to storage is being accomplished; and further provides that the same equipment may be used for controlling the well when a flow is to be obtained eitherthrough the casing or tubing individually or simultaneously, or closing oi the flow of uid through the casing or tubing individually or simultaneously so that any changes desired may be made in any of the valves in the Christmas tree assembly without losing control of the well.

The water which is circulated in the well passes down through the string of'tubing I3, through the back pressure valve and the stop cock I5 and issues through the nipple at the bottom of the tubing. As this water is discharged it will pass out at the base of the casing so that the mud will be removed fromV the area 21 between the casing and the formation wall 2. 'I'his mud may pass upwardly around the outside of the screen and into the casing at the upper end of the screen and will preferably discharge through -the iiow lines I0 and II.

discontinued. When the well has been completely Washed or is approaching a condition where it is completely washed, the most critical period arises and the possibility of a blowout is `most imminent. At this time it is necessary to position the tubing head so that the string of tubing will be properly suspended inside of the well in order to receive a flow of oil. In order to accomplish this it is necessary to attach a tubing hanger to the upper end of the string of tubing and to raise the string of tubing to a position similar to that shown in Fig. 2, wherein the lower end of the tubing and the nipple 25 will be positioned slightly above the perforations 9 in the casing or liner. It is intended that the positioning of the stop cock I5 and back pressure valve 20 in the string of tubing I3 will be such that when the nipple' 25 is positioned'at substantially its final elevation the stop cock and back pressure valve will be directly above the top of the.

tubing head 8, as seen in Fig. 2. With the parts in this position, the rams I4 oi.' the blowout preventer 5 will be moved inwardly to engage about the string of tubing and it is intendedV that a coupling 28 on the string of tubing I3 will also be so positioned in the string of tubing that it will be directly above the rams I4 at this period of the operation. The rams Il when thus closed about the tubing will serve as a support for the string of tubing due to the fact that this coupling 28 will be lowered onto the top of the rams and the entire string of tubing will be thus supported. v

Hose connection and vother ttings on the upper end of the string of tubing may now be removed, while the string of tubing is thus resting on the blowout preventer rams. Stop cock I5 is then closed. The back pressure valve 20 will also be removed and there can be no iow through the tubing at this time due to the stop cock I5 and there can be no ow through the casing 4 due to the rams Il of the blowout preventer so that the entire well area is closed oit in this manner. When the back pressure valve 20 is removed, a string will be removed from the upper end of the-tubing substantially equal to the distance the tubing has been raised from the washing position to the owing position.

By having reference to Fig. 3, the next step of the process will be apparent. This step lncludes the connection to the string of tubing of the tubing hanger 30. This hanger may be of any desired type but the one here illustrated is of special construction described in my co-pending application Serial No. 530,649, led April 16, 1931, patented May 16, 1933, United States Patent No. 1,909,304. This tubing hanger is connected as closely as possible above the stop cock I5 by a short section of pipe 3i. In event the type of tubing hanger shown in this Fig. 3 illustration is used the rams 32 will be moved to closed position as shown in the drawings. These rams when thus closed serve to close the passage through the tubing. The next step is to open the stop cock I5 so that a-passage will be available through the tubing. The tubing is now ready to be landed in its ilnal position and it is only necessary to retract the rams I4 of the blowout preventer so that their support will be withdrawn from beneath the coupling 28. When this occurs the weight of the tubing will cause it to drop so that the tubing hanger will seat in the bowl 33 oi. the tubing head 9.

It is to be understood that the rams I4 may be opened slowly if desired so as to cushion the lowering of a string of tubing or a suitable' elevator or other connection may be made so that any shock of landing the tubing will be avoided. In any instance it is substantially impossible for the -well to blow out during the instant when it is necessary to lower this tubing hanger into the tubing head. The flange 34 of the tubing hanger is arranged to engage the flange 35 on the tubing head and suitable bolts or other fastening elements may be passed therethrough in order to anchor the tubing to the Well head i'lttings. When the parts are thus positioned suitable valves, flow lines or other ttings may be attached above the tubing hanger 30. When all of these fittings have been properly positioned and in order, the rams 32 may be Withdrawn and the now of iiuid permitted through the tubing, or if it necessary to swab the well, the swab may be run down inside` of the tubing to start lthe nowing of the well.

Fig. 4 shows a slightly modified form of tubing hanger which is indicated at I' and'merely constitutes a hanger member similar to thel lower portion of the hanger It. The upper portion oi.' this hanger ll'. however, constitutes a head 35', which is not provided with any rams or blowout preventer means. This head 35 receives a nipple 3|, .which may in turn carry the valve 31 so that `flow through the tubing may be controlled by this valve in lieu of the rams 32 in the Fig. 3 construction.

.With the mechanisms and method of operation disclosed above, it seems readily apparent that a complete washing of the well may be accomplished, because the operator is ready, at all times during the washing of the well, to close the same on an instants notice so that he feels secure in continuing the washing operation even when a blowout is imminent. In the present practice. it is dangerous to attempt the washing of the well, for the washing cannot satisfactorily be completed because when the specific gravity of the fluid inthe well is decreased, the forma.- tion pressure may overcome the weight of the fluid, and it may be necessary to discontinue the washing before the screen has been cleaned. When the operator is assured that vhe has control of the well, he is not hesitant about continuing the washing, and in actual practice, it

has been found that, by completely washing the well, the production thereof has been doubled, because no clogging of the strainer or perforated pipeoccurs, and a free flow of oil is permitted. Furthermore, the perforated pipe is washed clean of obstruction as a last step inthe method, and the operator is assured that his strainer is in proper condition as well as his tubing, and that the full pressure of the formation will be admitted to the well bore. If it is desired to flow the well through the casing, the outlets IU and H may-be utilized. If, however, as is the general practice, it is desired to fi'ow the well through the tubing, suitable flow vlines will be connected above the tubing hanger 30 or the valve 37, and the fluid drawn off from the Well in this manner.

While it is contemplated that the invention, as disclosed in Figures 1 to 4, inclusive, will operate satisfactorily under a majority of working conditions, it may be desirable to position the gate valve 8' below the blowout preventer 5 in order that complete controlrof the well may be had. Figure shows the gate valve 8' positioned below the blowout preventer 5. The casing can be complet`ely closed when there is no pipe therein, and it would then be possible to repair or replace the blowout preventer 5. 'I'he occasion for such a set of circumstances, however, is very remote in that the blowout preventers, now in general use, and particularly of the type illustrated in the drawings herewith, have been found to be reliable and satisfactory.

'Ihe operation of the invention; with the gate valve positioned as shown in Figure 5 will be substantially the same as that described in connection with Figures 1 to 4. It is not believed, therefore, to be necessary to repeat in detail a description of the construction and operation of the various parts, as their manipulation has already been disclosed.

It is contemplated that this novel method may be practiced with other fittings than those here specifically disclosed, as the fittings have been shown for purposes of illustration only, and the invention shall only be restricted in scope by th substance of the appended claims.

Having described my invention, whatI claim is 1. In an apparatus for bringing in a well in formation having high pressure with a single string of tubing and without removing said string from the well, a casing h ving a casing head at the surface of the well, a strainer positioned at the lower end of said casing, a tubing including a lower string and an upper string detachably connected with said lower string, the bottom end of said lower string and the bottom end of said strainer being provided' with cooperating means to enable said lower string to seal in engagement with said strainer during outside washing of the well, said upper string of tubing serving to elevate said lower string of tubing from washing .position to flowing position, a blowout preventer adjacent the casing head comprising elements movable into engagement with said tubing for control between the outside of said tubing and the inside of said casing during the washing and elevating operations, and movable out of engagement with said tubing to pass tubing collars and the like past said blowout preventer,and means at said casing head to control flow through said tubing when said lower string is elevated to flowing position and said upper string is detached therefrom.

2. In an apparatus for bringing in a well in formation having high pressure with a single string of tubing and without removing said string from the well, a casing having a casing head at the surface of the well, a strainer positioned at the lower end of said casing, a tubing including a lower stringand an upper string detachably connected with said lower string, the bottom end of said lower string and the bottom end of said strainer being provided with cooperating means to enable said lower string to seal in engagement with said strainer during outside washing of the well, said upper string of tubing serving to elevate said lower string of tubing from washing position to flowing position, a blowout preventer adjacent the casing head comprising elements movable into engagement with said tubing for control between the outside of said tubing and the inside of said casing during the washing and elevating operations, and movable out of engagement with said tubing to pass tubing collars and the like past said blowout preventer, and means to close oil the upper end of said casing head when said lower string is elevated to flowing position and said upper string is detached therefrom.

3. In an apparatus for bringing in a well in formation having high pressure with a single string of tubing and without removing said string from the well, a casing having a casing head at the surface of the well, a strainer positioned at the lower end of said casing, a tubing including a lower string and an upper string detachably connected with said lower string, the bottom end of said lower string and the bottom end of said strainer being provided with cooperating means to enable said lower string to seal in engagement with said strainer during outside washing of the well, said upper string of tubing serving to elevate said lower string of tubing from washing position to flowing position, a blowout preventer adjacent the casing head comprising elements movable into engagement with said tubing for control between the outside of said tubing and the inside of said casing during the washing and elevating operations, and movable out of engagement with said tubing to pass tubing collars and amasar the like past said blowout preventer, and means to close o the upper end of said tubing when said lower string is elevated to flowing position and said upper string is detached therefrom.

4:. In an apparatus for bringing in a well in formation having high pressure with a single string of tubing and without removing said string from the well, a casing having a casing head at the surface of the well, a strainer positioned at the lower end of said casing, a tubing including a lower string and an upper string detachably connected with said lower string, thebottom end of said lower string and the bottom end of said strainer being provided with cooperating means to enable said lower string to seal in engagement with said strainer during outside washing of the well, a back pressure valve in said upper string, whereby washing fluid may be forced downwardly through said upper string and through said lower string while maintaining control against reverse flow through said tubing, said upper string of tubing serving to elevate said lower stringy of tubing from washing position to flowing position, a blowout preventer adjacent the casing head comprising elements movable into engagement with said tubing for control between the outside of said tubing and the inside of said casing during the washing and elevating operations, and movable out of engagement with said tubing to pass tubing collars and the like past said blowout preventer, and means at said casing head to control flow through said tubing when said lower string is elevated to flowing position and said upper string is detached therefrom.

5. Inl an apparatus for bringing in a well in formation having high pressure with a single string of tubing and without removing said string from the well, acasing having a casing head at the surface of the well, a strainer positioned at the lower end of said casing, a tubing including a lower string and an upper string detachably connected with said lower string, the bottom end of said lower string and the bottom end of said strainer being provided with cooperating means to enable said lower string to seal in engagement with said strainer during outside Washing of the well, said upper string of tubing serving to elevate said lower string of tubing from washing position to flowing position and being of length substantially equal to the distance said lower string is elevated, a blowout preventer adjacent the casing head comprising elements movable into engagement with said tubing for control between the outside of said tubing and the inside of said casing during the washing and elevating operations, and movable out of engagement with said tubing to pass tubing collars and the like past said blowout preventer, and means to close off the upper end of said casing head when said lower string is elevated to flowing position and said upper string is detached therefrom.

6. In an apparatus for bringing in a well in formation having high pressure with a single string of tubing and without removing said string from the well, a casing having a casing head at the surface of the well, a strainer positioned at -the lower end of said casing, a tubing including a lower string and an upper string detachably connected with said lower string, the bottom end of said lower string and the bottom end of said strainer being provided with cooperating means to enable said lower string to seal in engagement with said strainer during outside washing of the well, said upper string of tubing serving to elevate said lower string of tubing from washing position to owing position, a blowout preventer adjacent `the casing head comprising elements movable into engagement with said tubing for control between the outside of said tubing and the inside of said casing during the washing and elevating operations, and movable out of engagement with said tubing tolpass tubing collars and the like past said blowout preventer, and means to control flow through said tubing while said lower string is being elevated to flowing position and said upper string is being detached therefrom. l

7. In an apparatus for bringing in a well in formation having high pressure with a single string of tubing and without removing said string from the well, a casing having a casing head at the surface of the well, a strainer positioned at the lower end of said casing, a tubing .including a lower string and an upper string detachably connected with said lower string, the bottom end of said lower string and the bottom end of said strainer being provided with cooperating means to enable said lower string to seal in engagement with said strainer during outside washing of the well, said upper string of tubing serving to elevate said lower string of tubing from washing position to flowing position and. being of length substantially equal to the distance said lower string is elevated, a blowout preventer adjacent the casing head comprising elements movable into engagement with said tubing for control between the outside of said tubing and the inside of said casing during the washing and elevating operations, and movable out of engagement with said tubing to pass tubing collars and the like past said blowout preventer, and means in said tubing to control against upward flow of fluid therethrough from the well during the washing and elevating operations and while said upper string of tubing is being detached from said lower string of tubing.

. ROBERT A. MUELLER. 

